A plug-coupling arrangement is generally used to couple mechanical vacuum pumps with the crankshaft or the drive shaft of the internal combustion engine for conjoint rotation. The plug-coupling arrangement is formed by plug-coupling elements which are designed to be complementary to each other, having one or a plurality of claws engaging into corresponding recesses of the respective other plug-coupling element. For a facilitation of assembly and for a mechanical decoupling of the pump rotor from the corresponding shaft, the plug-coupling arrangement has radial and axial play so that friction occurs in the area of the plug-coupling arrangement that makes lubrication necessary.
A mechanical vacuum pump for motor vehicles is described in WO 2014/063681 A1 which comprises a lubricant supply in which the liquid lubricant is transferred through a stationary lubricant supply channel in the pump housing into a rotating lubricant transport channel in the pump rotor, through which the lubricant is directed axially into the center of the plug-coupling arrangement to between the two plug-coupling elements. This structure is comparatively complex and the retaining bolt which is exposed to great mechanical stress is mechanically weakened by the axial bore. The lubricant must also be pumped into the axial center of the rotating pump rotor so that, in particular at high rotational speeds, substantial centrifugal forces must be overcome that act on the lubricant.